[1] Univ Florida, Dept Neurosurg, Coll Med, Gainesville, FL 32610 USA
[2] Tulane Univ, Sch Med, Dept Neurol Surg, 1430 Tulane Ave, New Orleans, LA 70112 USA
[3] Univ Iowa, Carver Coll Med, Dept Neurosurg, Iowa City, IA USA
[4] Thomas Jefferson Univ, Sidney Kimmel Med Coll, Dept Neurol Surg, Philadelphia, PA 19107 USA
[5] Univ Miami, Dept Neurol Surg, Miller Sch Med, Coral Gables, FL 33124 USA